1. Field of the Invention
The present invention relates to an electronic part module, in particular an electronic module which contain a plurality of device chips and a plurality of passive parts as their constituent elements. The present invention also relates to a manufacturing method of the electronic part modules.
2. Description of the Related Art
Our information society is dependent upon a variety of information processing equipment including mainframe computers, personal computers and mobile communication terminals. In all of these fields, efforts are being made for higher processing speed, smaller size of equipment, increased versatility, reduced power consumption, and so on. All of these improvements are mainly dependent upon improved level of circuit integrity and performance (higher speed, advanced functionality, etc.) of numerous semiconductor devices incorporated in the equipment and apparatuses. Multi-chip module (MCM) technology is known to be one of the means for achieving such goals as improved level of circuit integrity and performance of semiconductor devices. MCM technology is disclosed in e.g. the following Patent Documents 1 and 2:    Patent Document 1: JP-A-H10-294421    Patent Document 2: JP-A-2000-36657
MCMs generally include a wiring substrate as a base substrate of the entire module, a plurality of device chips mounted on the wiring substrate in the form of bear chips, and a plurality of passive parts (capacitors, inductors, resistors, etc.) There are different types of MCMs; MCM-L (MCM-Laminated), MCM-C (MCM-Ceramic), and MCM-D (MCM-Deposited). Categorization into these three types is based upon the build of their wiring substrate serving as a base substrate.
MCM-L uses a wiring substrate manufactured from a resin substrate made of laminated resin material, as the base substrate for the entire module. The wiring substrate includes wiring on and/or inside the resin substrate, to which device chips are mounted as bear chips. Passive parts mounted on the wiring substrate are generally individual products manufactured as devices for surface mounting. Sometimes, the passive parts are placed inside the wiring substrate.
If an MCM-L is configured by using individual passive parts which are produced separately for surface mounting on a wiring substrate, it is sometimes impossible to accomplish sufficient size reduction of the module since surface mount type passive parts are relatively large individual chips each having their own substrate where their structures are built.
If an MCM-L is configured by using passive parts which are placed inside the wiring substrate, it is sometimes impossible for the module to perform sufficiently. In the wiring substrate, spaces between the passive devices, wires, and space between a pair of electrodes in each capacitor are all filled with a resin material (dielectric material) that constitutes the wiring substrate. Although this is preferable for capacitors inside the wiring substrate because a high dielectric constant of the resin material allows to obtain a large electrostatic capacity, it is not preferable for other passive devices (particularly for inductors) and the wires inside the wiring substrate because a low dielectric constant is desirable in order to reduce parasite capacities between the passive devices and wires. As described, two mutually conflicting requirements must be met by the resin material which constitutes the wiring substrate in order to achieve the goal of improved performance. In addition, for inductors embedded in the wiring substrate, there is a problem of decreased Q factor caused by parasite capacities. For these reasons, an MCM-L having its passive parts incorporated within the wiring substrate is sometimes not capable of performing sufficiently.
MCM-C uses a wiring substrate manufactured from a ceramic substrate as the base substrate for the entire module. Types of the wiring substrate for MCM-C include a single-layer ceramic substrate having a surface provided with a thick film wiring by printing, and a multilayer substrate constituted by a plurality of co-sintered ceramic substrates each having a surface printed with a wiring pattern. On such a wiring substrate, device chips are mounted as bear chips. Passive parts mounted on the wiring substrate are generally individual products manufactured separately as surface mount devices. Sometimes, the passive parts are built inside the wiring substrate.
If an MCM-C is configured by using individual passive parts which are produced separately for surface mounting on a wiring substrate, it is sometimes impossible to accomplish sufficient size reduction of the module since the surface mount type passive parts are, as described above, relatively large individual chips each having their own substrate where their structures are built.
If an MCM-C is configured by using passive parts which are built inside the wiring substrate, it is sometimes impossible for the module to perform sufficiently. In the wiring substrate, spaces between the passive devices, wires, and space between a pair of electrodes in each capacitor are all filled with a ceramic material (dielectric material) that constitutes the wiring substrate. Although this is preferable for capacitors inside the wiring substrate because a high dielectric constant of the ceramic material allows to obtain a large electrostatic capacity, it is not preferable for other passive devices (particularly for inductors) and the wires inside the wiring substrate because a low dielectric constant is desirable in order to reduce parasite capacities between the passive devices and wires. As described, two mutually conflicting requirements must be met by the ceramic material which constitutes the wiring substrate in order to achieve the goal of improved performance. In addition, for inductors embedded in the wiring substrate, there is a problem of decreased Q factor caused by parasite capacities. For these reasons, an MCM-C having its passive parts incorporated within the wiring substrate is sometimes not capable of performing sufficiently.
MCM-D uses a wiring substrate made of a base member provided by ceramic, silicon, glass or other material, as the base substrate for the entire module. A multilayer wiring structure is formed on the base member by means of thin-film layering technology. The multilayer wiring structure generally includes a plurality of thin-film wiring layers, insulating layers each separating mutually adjacent wiring layers, and vias which connect wiring layers. On a wiring substrate having such a multilayer wiring structure, device chips are mounted as bear chips. Passive parts are either mounted on the wiring substrate as individual products manufactured as surface mount devices, or built inside the multilayer wiring structure.
If a MCM-D is configured by using individual passive parts which are produced separately for surface mounting on a wiring substrate, it is sometimes impossible to accomplish sufficient size reduction of the module since surface mount type passive parts are relatively large as described above.
If an MCM-D is configured by using passive parts which are built inside the multilayer wiring structure, it is sometimes impossible for the module to perform sufficiently. In the multilayer wiring structure, spaces between the passive devices, wires, and space between a pair of electrodes in each capacitor are all filled with an insulation material (dielectric material) that constitutes the insulation layer. Although this is preferable for capacitors which are placed inside the multilayer wiring structure because a high dielectric constant of the resin material allows to obtain a large electrostatic capacity, it is not preferable for other passive devices (particularly for inductors) and the wires in the multilayer wiring structure because a low dielectric constant is desirable in order to reduce parasite capacities between passive devices and wires. As described, two mutually conflicting requirements must be met by the insulation material in the multilayer wiring structure resin based wiring substrate in order to achieve the goal of improved performance. In addition, for inductors embedded in the wiring substrate, there is a problem of decreased Q factor caused by parasite capacities. For these reasons, an MCM-D having its passive parts incorporated within the multilayer wiring structure are sometimes not capable of performing sufficiently.